Acquired, involuntary sinusoidal oscillation of the eyes in human patients, commonly referred to as acquired pendular nystagmus (APN), produces an illusion to the patient that his/her surroundings are in motion (oscillopsia) and degrades clarity of vision. Although the exact mechanism of APN is not well understood, it is a neurologic disorder that is often secondary to multiple sclerosis.
Typically, the eyes of a patient suffering from APN will oscillate at a frequency of between 2 and 7 hertz, with amplitudes as high as eight degrees. Consequently, APN is a debilitating disease that prevents people from reading books, watching television, driving, and otherwise participating in everyday activities.
Heretofore, APN has been treated with drugs and/or special spectacles/contact lenses. These prior treatments have been found to be ineffective or suboptimal. A large number of drugs have been reported to treat APN, but efficacy is variable, often incomplete, and some patients fail to respond to all agents. Many patients that do respond to APN drugs have not been able to tolerate the medication on a daily basis due to sedation or ataxia. Other treatment strategies, including weakening selected extraocular muscles with botulinum toxin or using spectacle/contact lens combinations to optically attenuate the visual consequences of APN have proved to be impractical and have failed to gain wide patient acceptance, A main disadvantage of existing surgical and optical APN treatments is that they also impair normal reflex and voluntary eye movements as much as they reduce pathological nystagmus. For example, when treating APN with a spectacle/contact lens combination, the vestibulo-ocular reflex is nullified and, thus, any patient head movements generate oscillopsia.
In light of the foregoing, a need has been identified for a non-surgical non-pharmacologic treatment for APN that reduces oscillopsia and improves acuity, with few or minimal adverse effects. Particularly, a need has been found for a convenient and effective APN treatment device that is wearable by a patient to negate the deleterious effects of APN.
In accordance with the present invention, a novel and non-obvious non-invasive acquired pendular nystagmus treatment device is provided.
In accordance with another aspect of the present invention, a novel and non-obvious method for treating acquired pendular nystagmus is provided that utilizes a specially designed non-invasive device.
In accordance with still another aspect of the present invention an apparatus for treating acquired pendular nystagmus associated with an eye of a patient is provided. The apparatus includes a sensor for tracking oscillating movement of the eye in at least one plane and outputting an eye movement signal that varies with the oscillating eye movement. An optic assembly is adapted for operative placement relative to the eye of the patient and for translating an image perceived by a patient with his/her eye in the at least one plane in correspondence with the oscillating eye movement. An optic assembly control circuit is operatively connected between the sensor and the optic assembly. The control circuit is adapted for receiving the eye movement signal and controlling the optic assembly in response to the eye movement signal to translate the image perceived by the patient in a manner that corresponds with the oscillating eye movement.
In accordance with still another aspect of the present invention, a method of treating an eye movement disorder associated with an eye of a patient includes tracking involuntary movements of the eye in at least one plane. The method further includes optically translating an image perceived by the patient with the eye in the at least one plane and in correspondence with the tracked involuntary movements of the eye in the at least one plane.
In accordance with yet another aspect of the present invention, an apparatus for treating an involuntary eye movement disorder of a patient is provided. The apparatus includes a sensor for tracking involuntary movement of the patient""s eye in at least one plane and outputting a control signal that varies with the tracked involuntary eye movement. The apparatus also includes an optic assembly adapted for operative placement relative to the patient""s eye and for translating an image perceived by the patient in the at least one plane in correspondence with the involuntary eye movement. An optic assembly control circuit is provided and operatively connected between the sensor and the optic assembly. The control circuit is adapted for receiving the control signal and controlling the optic assembly in response to the control signal to translate the image perceived by the patient in a manner that corresponds with the involuntary eye movement.
One advantage of the present invention resides in the provision of a non-invasive device for treating acquired pendular nystagmus without surgery or drugs.
Another advantage of the present invention is found in the provision of a method for treating acquired pendular nystagmus using a specially designed device.
A further advantage of the present invention is the provision of a method and apparatus for treating acquired pendular nystagmus wherein normal reflex and voluntary eye movements are not impaired.
Another advantage of the present invention resides in the provision of a device for treating acquired pendular nystagmus that is wearable by the patient.
Still other benefits and advantages of the present invention will become apparent to those of ordinary skill in the art to which the invention pertains upon reading and understanding the following specification.